Synthetic method of 3, 4-methylene dioxybenzaldehyde

Abstract

The invention discloses a synthetic method of 3, 4-methylene dioxybenzaldehyde and relates to the field of chemical organic synthesis, and particularly relates to a synthetic method in which an intermediate generated in a process of preparing 3, 4-methylene dioxybenzaldehyde by taking catechol methylene ether as a raw material is oxidized by suing a nitryl-free oxidizing agent to generate the final product. According to the synthetic method of 3, 4-methylene dioxybenzaldehyde, oxidative decarboxylation is carried out on the intermediate piperonyl mandelic acid (prepared from catechol methylene ether) as an initial reactant in the presence of at least one catalyst selected from metal chloride Lewis acid and at least one oxidizing agent selected from oxygen and peroxides in an acidic environment so as to synthesize 3, 4-methylene dioxybenzaldehyde. The synthetic method provided by the invention is simple in technical step, thorough in conversion of the raw materials, high in finished product yield and short in technical time, and the product does not contain color-changing impurities and is stable in technical quality.

Description

technical field [0001] The invention relates to the field of chemical organic synthesis, in particular to oxidizing intermediates produced in the process of preparing 3,4-methylenedioxybenzaldehyde with catechol methylene ether as raw materials by using nitro-free oxidizing agents Synthesis method to obtain the final product. Background technique [0002] The traditional technology of synthesizing 3,4-methylenedioxybenzaldehyde (also known as jasmonal, piperonal) with catechol methylene ether (also known as piperonyl) as the basic raw material is generally Phenoxymethyl ether is first reacted with glyoxylic acid under strong acid conditions to obtain piperonyl mandelic acid, then decarboxylated under nitric acid conditions at high temperature to obtain crude piperonal, and then rectified and recrystallized to obtain the finished product. For example, Shan Shaojun et al. used piperonylcycline to generate intermediates with glyoxylic acid in [Research on a new process for the...

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Problems solved by technology

For example, Shan Shaojun et al. used piperonylcycline to generate intermediates with glyoxylic acid in [Research on a new process for the synthesis of jasmonal], and then decarboxylated under the action of silver nitrate to obtain crude piperonal. This process has a long reaction time and the original The auxiliary materials are expensive, and the process yield is low. Wang Shuai reported a new process method for the synthesis of piperonal by air catalytic oxidation in the article [Air Catalytic Oxidation Synthesis of Jasminal]. The main problem is that the intermediate raw materials need to be strictly purified. Disadvantages such as processing and long process time; Japanese patent [preparation method of piperonal] patent number: CN01804348.8 introduces a synthetic method of piperonal, piperonyl first synthesizes an intermediate with glyoxylic acid, and then adds a solvent for processing, Finally, decarboxylation under nitric acid conditions obtains crude piperonal. The main problem of the process is that the use of a large amount of solvents leads to a decline in production efficiency and a substantial increase in energy consumption; Hydroquinone methylene ether, hydrochloric acid, acetic acid, hexamethylenetetramine, tetrabutylammonium bromide, chloroform, etc. are used as raw materials and reaction reagents to synthesize piperonal. The process is complicated, environmental protection, and many potential safety hazards, so it is not suitable for industrial production ; Patent CN: 201110313057.3 [a kind of method that fully synthesizes and prepares jasmonal] adopts piperonylcycline to carry out condensation reaction with dichloromethane, acetic anhydride, catalyzer at first, the intermediate that obtains reacts with chlorine again, and the intermediate that obtains passes alkali again Hydrolysis, acidification with hydrochloric acid, and finally heating and decarboxylation in nitric acid to obtain crude piperonal. The process is complicated, the yield is low, environmental protection, and many safety hazards

[0003] There are some unsolvable problems in the above-mentioned traditional technology and the recent research technology, especially in the deacidification of the intermediate piperonyl mandelic acid prepared by using catechol methylene ether as raw material under nitric acid conditions, which will inevitably lead to A small amount of piperonyl nitro compounds remain, resulting in discoloration of the product. This is a common problem in the nitric acid decarboxylation process, and there is no better way to solve it

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